An aperture-matched compact range feed horn design

The moment method and the uniform geometrical theory of diffraction are used to obtain two separate solutions for the -plane far field pattern of an aperture-matched horn antenna. This particular horn antenna consists of a standard pyramidal horn with the following modifications: a rolled edge section attached to the aperture edges and a curved throat section. The resulting geometry provides significantly better performance in terms of the pattern, impedance, and frequency characteristics than normally obtainable. The moment method is used to calculate the -plane pattern and voltage standing-wave ratio (VSWR) of the antenna. However, at higher frequencies, the moment method requires large amounts of computation time. On the other hand, the uniform geometrical theory of diffraction provides a quick and efficient high frequency solution for the -plane field pattern. In fact, the uniform geometrical theory of diffraction may be used to initially design the antenna; then the moment method may be applied to "fine tune" it. In both methods, a two-dimensional -plane model of the antenna is used, but these two-dimensional solutions yield excellent agreement with measured data of the actual three-dimensional antenna. This procedure has been successfully applied to design a compact range feed horn.